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/*
* Copyright (C) 2003 PMC-Sierra Inc.
* Author: Manish Lachwani (lachwani@pmc-sierra.com)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Detailed Description:
*
* This block implements the I2C interface to the slave devices like the
* Atmel 24C32 EEPROM and the MAX 1619 Sensors device. The I2C Master interface
* can be controlled by the SCMB block. And the SCMB block kicks in only when
* using the Ethernet Mode of operation and __not__ the SysAD mode
*
* The SCMB controls the two modes: MDIO and the I2C. The MDIO mode is used to
* communicate with the Quad-PHY from Marvel. The I2C is used to communicate
* with the I2C slave devices. It seems that the driver does not explicitly
* deal with the control of SDA and SCL serial lines. So, the driver will set
* the slave address, drive the command and then the data. The SCMB will then
* control the two serial lines as required.
*
* It seems the documents are very unclear abt this. Hence, I took some time
* out to write the desciption to have an idea of how the I2C can actually
* work. Currently, this Linux driver wont be integrated into the generic Linux
* I2C framework. And finally, the I2C interface is also known as the 2BI
* interface. 2BI means 2-bit interface referring to SDA and SCL serial lines
* respectively.
*
* - Manish Lachwani (12/09/2003)
*/
#include "i2c-yosemite.h"
/*
* Poll the I2C interface for the BUSY bit.
*/
static int titan_i2c_poll(void)
{
int i = 0;
unsigned long val = 0;
for (i = 0; i < TITAN_I2C_MAX_POLL; i++) {
val = TITAN_I2C_READ(TITAN_I2C_COMMAND);
if (!(val & 0x8000))
return 0;
}
return TITAN_I2C_ERR_TIMEOUT;
}
/*
* Execute the I2C command
*/
int titan_i2c_xfer(unsigned int slave_addr, titan_i2c_command * cmd,
int size, unsigned int *addr)
{
int loop = 0, bytes, i;
unsigned int *write_data, data, *read_data;
unsigned long reg_val, val;
write_data = cmd->data;
read_data = addr;
TITAN_I2C_WRITE(TITAN_I2C_SLAVE_ADDRESS, slave_addr);
if (cmd->type == TITAN_I2C_CMD_WRITE)
loop = cmd->write_size;
else
loop = size;
while (loop > 0) {
if ((cmd->type == TITAN_I2C_CMD_WRITE) ||
(cmd->type == TITAN_I2C_CMD_READ_WRITE)) {
reg_val = TITAN_I2C_DATA;
for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW;
++i, write_data += 2, reg_val += 4) {
if (bytes < cmd->write_size) {
data = write_data[0];
++data;
}
if (bytes < cmd->write_size) {
data = write_data[1];
++data;
}
TITAN_I2C_WRITE(reg_val, data);
}
}
TITAN_I2C_WRITE(TITAN_I2C_COMMAND,
(unsigned int) (cmd->type << 13));
if (titan_i2c_poll() != TITAN_I2C_ERR_OK)
return TITAN_I2C_ERR_TIMEOUT;
if ((cmd->type == TITAN_I2C_CMD_READ) ||
(cmd->type == TITAN_I2C_CMD_READ_WRITE)) {
reg_val = TITAN_I2C_DATA;
for (i = 0; i < TITAN_I2C_MAX_WORDS_PER_RW;
++i, read_data += 2, reg_val += 4) {
data = TITAN_I2C_READ(reg_val);
if (bytes < size) {
read_data[0] = data & 0xff;
++bytes;
}
if (bytes < size) {
read_data[1] =
((data >> 8) & 0xff);
++bytes;
}
}
}
loop -= (TITAN_I2C_MAX_WORDS_PER_RW * 2);
}
/*
* Read the Interrupt status and then return the appropriate error code
*/
val = TITAN_I2C_READ(TITAN_I2C_INTERRUPTS);
if (val & 0x0020)
return TITAN_I2C_ERR_ARB_LOST;
if (val & 0x0040)
return TITAN_I2C_ERR_NO_RESP;
if (val & 0x0080)
return TITAN_I2C_ERR_DATA_COLLISION;
return TITAN_I2C_ERR_OK;
}
/*
* Init the I2C subsystem of the PMC-Sierra Yosemite board
*/
int titan_i2c_init(titan_i2c_config * config)
{
unsigned int val;
/*
* Reset the SCMB and program into the I2C mode
*/
TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0xA000);
TITAN_I2C_WRITE(TITAN_I2C_SCMB_CONTROL, 0x2000);
/*
* Configure the filtera and clka values
*/
val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_A);
val |= ((val & ~(0xF000)) | ((config->filtera << 12) & 0xF000));
val |= ((val & ~(0x03FF)) | (config->clka & 0x03FF));
TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_A, val);
/*
* Configure the filterb and clkb values
*/
val = TITAN_I2C_READ(TITAN_I2C_SCMB_CLOCK_B);
val |= ((val & ~(0xF000)) | ((config->filterb << 12) & 0xF000));
val |= ((val & ~(0x03FF)) | (config->clkb & 0x03FF));
TITAN_I2C_WRITE(TITAN_I2C_SCMB_CLOCK_B, val);
return TITAN_I2C_ERR_OK;
}
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